Fastener for dental instruments.



' strument to the handle thereof; and it con- UNITED STATES PATENT OFFICE.

JAMES W. IVORY, OF PHILADELPHIA, PENNSYLVANIA.

FASTENER FOR- DENTAL INSTRUMENTS.

SPECIFIGATION forming part of Letters Patent No. 634,732, dated October 10, 1899.

Application filed June 7, 1899. Serial No. 719,665 (No model.) i

in the city and county of Philadelphia, State L of Pennsylvania, have invented a new and useful Improvement in Fasteners for Dental Instruments, which improvementis fully set forth in the following specification and accompanying drawings.

- My invention relates to an improvement in means employed for fastening a dental inand a screw-threaded shank on the instruinent, said shank carrying said nut and engaging the handle,and said collar being adapted to tighten against the end of the handle, thus providing a firm and reliable connection for the instrument and preventing wabhling thereof.

Figure 1 represents a perspective view of a fastening for a dental instrument embodying my design. Fig. 2 represents a longitudinal section of a portion on an enlarged scale. 'Fi g. 3 represents a perspective view of the fastening and adjacent portions and a section of part, of the handle. V

Similar letters of reference indicate corresponding parts in the figures.

Referring to the drawings, A designates a handle, the fore part of which has the bore B therein, the wall of a portion of the latter being threaded, as at C. v

. D designates a dental instrument which is provided with the screw-threaded shank E,

which enters said bore B and engages with the threads 0 thereof, thus connecting said instrument with said handle. On the threaded portion of the shankis the nut F, on whose rear or inner end is the conical collar, which is adapted to engage the forward end of the handle A, said end being preferably beveled, as at H, so that said collar is enabled to take firm hold of said end. l

The operation is as follows: The shank is inserted into the bore B and screwed thereto to full extent, when the nut F is tightened and wedged against the end of the handle, thus clamping the instrument to the handle and causing the same to retain its position on the latter in a steady and reliable manner without liability to wabble, shake, etc. The

nut may, however, be left partly on the threaded portion of the shank, as shown in dotted lines, Fig. 3. In this case the instru ment may be held by one hand and the handle grasped by theother hand and rotated so that it will screw upon the shank of the instru-- ment and turn the nut with it to full extent,

when therewill be a locking engagement of effective wedging, a close fit, and a tight bind= ing of said parts.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1 A fastening for a dental instrument con sisting of a nut, a threaded shank on said in strument on which said nut is fitted, and a handle with a threaded bore receiving said shank, said nut having a conical collar which is adapted to wedge with the adjacent end of said handle.

2. A dental instrument provided with a screw-threaded shank and a nut thereon, the latter having a collar which is adapted to tighten against the handle of said instrument and which receives said shank.

3. Adentalinstrumenthavingontheshank thereof, a nut which is provided with a couical collar for tightening the instrument on the handle which carries it.

. JAMES w. IVORY.

Witnesses:

JOHN A. Wrnnnnsiianrn, WM. 0. W IEDERSHEIM. 

